中
=
丨
+
口
:
Mnemonic symbol: a dart board, because you always try to hit the center.
Julian Giant Squid (zhu-) is throwing dinosaur bones (丨) as darts on a dart board in front of the engine ((e)ng1). To make it a bit more difficult he's throwing mandarins (口) into the air as well and skewers them up right in the center (中 is a mandarin skewered on a dinosaur bone) in mid flight with the dinosaur bones. He's still able to consistently hit the center (中) of the dart board.
国
=
囗
+
玉
:
Mnemonic symbol: a nation's flag. Let's say the Chinese flag.
In the observatory's kitchen (o2) Gitta Giraffe (gu) is practising her ballet performance. She got a whole crate (囗) full of jade bracelets (玉) and flags (国) and fixed one flag to each jade bracelet. This makes a perfect combination for throwing the ring with the flag waving behind it and catching the ring again after a few pirouettes.
菜
=
艹
+
采
:
The King oh Chu (c) is busy preparing a dish (菜) in the airplane's bathroom (ai4). He is using two plectrums (采) to pluck out parts of a mat of artificial lawn (艹).